These data were downloaded from the Seabird SeaFET deployed at station KALD2 (Kaktovik Lagoon) from 7 August 2018 until 10 August 2019. A single point calibration was instituted during post-processing in the Kelley Lab to obtain calibrated pH values.
Upon instrument initiation, pH values change in linear fashion before becoming more stable, which may indicate instrument conditioning. pH values co-vary with salinity. Should these data be omitted?
To remove any doubt that the instrument was conditioning, I suggest removing the first 8 hours of samples.
pH data summary by month. July is most variable month. November-March is relatively stable.
| month | min.pH | max.pH | median.pH | min.sal | max.sal | median.sal | min.temp | max.temp | median.temp |
|---|---|---|---|---|---|---|---|---|---|
| January | 7.603 | 7.766 | 7.692 | 36.2 | 38.4 | 37.0 | -2.1 | -1.8 | -2.0 |
| February | 7.571 | 7.813 | 7.714 | 38.2 | 38.7 | 38.5 | -2.1 | -1.8 | -2.0 |
| March | 7.566 | 7.852 | 7.750 | 37.8 | 39.2 | 38.9 | -2.1 | -1.8 | -2.0 |
| April | 7.438 | 7.816 | 7.599 | 38.9 | 39.2 | 39.1 | -2.1 | -1.8 | -1.9 |
| May | 7.506 | 8.032 | 7.597 | 38.3 | 39.2 | 39.0 | -1.8 | -1.3 | -1.8 |
| June | 7.695 | 8.208 | 7.845 | 34.6 | 39.0 | 38.3 | -1.3 | 4.2 | -0.4 |
| July | 7.597 | 8.326 | 7.999 | 21.8 | 37.7 | 32.4 | 1.7 | 12.1 | 9.0 |
| August | 7.542 | 8.401 | 8.052 | 5.5 | 37.1 | 21.1 | 2.2 | 11.8 | 4.7 |
| September | 7.943 | 8.296 | 8.077 | 12.9 | 28.5 | 19.6 | -0.9 | 3.4 | 1.6 |
| October | 7.984 | 8.359 | 8.115 | 19.3 | 31.5 | 30.9 | -1.6 | -0.5 | -1.4 |
| November | 7.680 | 8.088 | 7.892 | 31.5 | 33.8 | 32.3 | -1.8 | -1.0 | -1.5 |
| December | 7.559 | 7.856 | 7.732 | 33.8 | 36.3 | 35.0 | -2.0 | -1.5 | -1.9 |
July is most hydrographically vairable month. August appears to have the most variability, but there are two years of data grouped in that month– two very different years. November through May are quite static in T & S compared to the rest of the year, although pH does vary during this time. The gradual decrease of pH during the under-ice season could be from continued respiration as photosynthesis ceases during the polar night. The introduction of alkaline river water to the lagoons during break-up and continued summer river/groundwater flow increases pH again, although it is curious there is not a strong relationship between pH~S during any month. This indidcates bioligical processes are significant modulators of pH.
Click and rotate graph to explore!